Personalized medicine is the customization of treatment to an individual as opposed to the one treatment-for-all model. Personalized medicine involves categorizing a patient based on his or her physical condition and designing an optimal healthcare solution exclusively for that category. The progression of personalized medicine is dependent on the discovery, validation, and commercialization of biomarkers to stratify populations for treatment and for the development of diagnostics for screening and early detection.
Epigenetic research has come to the forefront of medical research and is implicated in the etiology of a number of physical and mental illnesses including: cancer, obesity, diabetes, schizophrenia, and Alzheimer's disease (Alika et al., 2010; Grant et al. 2010; McGowen et al., 2009; McGowen and Szyf, 2010; Plazas-Mayorca and Vrana, 2011; and Portela and Esteller, 2010). In addition, Epigenetics may hold particular promise in the many scientific and medical areas including but not limited to: cancer, diabetes, drug integrations, drug effectiveness, childhood aggression, suicidal behaviors, aging, inflammation, pain, obesity, schizophrenia, and other mental illnesses (Abdolmaleky et al., 2005; Costa et al., 2003; Iwamoto & Kato, 2009; Kuratomi et al., 2007; McGowan & Kato, 2007; McGowen and Szyf, 2010; Peedicayil, 2007; Petronis et al., 1999; McGowen and Szyf, 2010; Plazas-ayorca and Vrana, 2011; and Zawia et al., 2009).
A major challenge in the field includes the identification of an appropriate source material for home-based sample collection that is adequate for large-scale epigenetic research including whole-genome-analysis studies. Epigenetics may be the key for understanding the mechanisms of gene-environment interactions as growing evidence suggests that epigenetic mechanisms may provide a molecular memory of environmental experiences (Ho, 2010; Kappeler and Meaney, 2010; McGowen et al., 2009, McGowen and Szyf, 2010; Portela and Esteller, 2010; Richards, 2008; Russo et al., 2010; Tsai et al, 2010; and Vlaanderen et al., 2010). Preliminary data from some humans suggest that distinct methylation patterns in peripheral blood cells are associated with social behaviors including: childhood aggression, suicidal behaviors, and ageing (Kappeler and Meaney, 2010; McGowen et al., 2009; McGowen and Szyf, 2010; Portela and Esteller, 2010; Russo et al., 2010, Tierling et al., 2010; Tsai et al, 2010; and Zhang et al., 2011).
Due at least in part to the heterogeneous nature of human disease, particularly mental illness, and the complex interaction of contributing etiological factors, studies require large sample sizes to provide reliable and significant effects. However, current research options for sample collection for epigenetic studies do not meet this requirement of “large sample sizes.” The need for large sample sizes for studies is also true in order to produce significant effects in regards to studying human-environment interactions as these interactions are also of a very complex nature with many contributing factors. The ability to perform large-scale “population sized” (subject samples numbering in at least the hundreds to thousands) epigenetic research can introduce a new understanding of human-environment interaction and facilitate the completion of longitudinal studies facilitating the development of epigenetic-based screening diagnostics crucial to the progression of modern medicine. This epigenetic research may lead to a new understanding of how the environment affects our epigenome and how this relates to a person's health outcome, which may further lead to the development of preventative interventions for individuals who are considered high-risk and diagnostics for these health disparities including, but not limited to, diagnosis.
Some epigenetic studies attempting to quantify environmental and other complex interactions in human populations use blood as the source material for experimentation. Blood can restrict the researcher's ability to conduct large population-sized studies as it:                1. generally requires medical supervision,        2. involves invasive procedures for collection,        3. carries stigma that limits participation, and        4. is expensive to collect and ship.        
Naturally expressed bodily fluids, e.g., saliva and urine, can be an additional or alternative appropriate source material for home-based sample collection as they:                1. do not require invasive techniques,        2. do not have the same stigma as blood,        3. do not require professional supervision, and        4. can be inexpensive to collect.        
In addition, at least saliva has been shown to contain white blood cells (Dos-Santos et al., 2009). The use of bodily fluids, e.g., saliva, urine, may enable large-scale “population-sized” epigenetic research. In addition, home-base sample collection of saliva, or urine, may allow for a much wider range of research options available as it can greatly increase participant numbers and samples can be more easily shipped by the subjects from anywhere in the world. For example, the ability to more easily ship samples from anywhere in the world can be particularly useful when samples are from countries that do not have laboratory infrastructure.
An organism's genome is a fixed sequence that contains its hereditary information and is the same in every cell of an organism. An organism's epigenome, by contrast, varies between cell types and changes over the organism's lifetime. Thus, epigenetic studies may include a single cell type as the source of sample material to control for these differences (Johnson and Tricker, 2010; Lister et al., 2009; and Rangwala et al., 2006). For example, human saliva contains numerous cell types, including epithelial cells, cells normally found in the blood (i.e., T-cells and B-cells), bacteria and debris (Dos-Santos et al., 2009 and Viet and Schmidt, 2008). The cells in saliva that are the most important to profile epigenetically are those that come from the blood stream, as these cells carry epigenetic information from the entire body (Kappeler and Meaney, 2010; McGowen and Szyf, 2010; McGowen and Szyf, 2010; Righini et al, 2007; Rosas et al., 2011, Vlaanderen et al., 2010 and Zhang et al., 2011).
Additionally, it may not be practical to use whole saliva DNA as the cells in saliva that are not found in the blood, such as epithelial cells, which make up the vast majority of cells in saliva (Dos-Santos et al., 2009) have the ability to “mask” the epigenetic effects seen in T-cells (cells that originated in the blood) by dampening the effect of the minority of cells (Dos Santos et al., 2009, Lister et al., 2009; and Tierling et al., 2010). To address these concerns AboGen developed a method to separate and extract the different cell types found in bodily fluids such as saliva by taking advantage of cell-specific markers and isolation techniques (e.g., magnetic). This method uses practical amounts of bodily fluids, such as saliva, to yield enriched cells that can be used for downstream biological applications including large-scale functional genomic studies (example epigenomic studies). For example, saliva sample processing technology allows collected samples to be processed into single cell types and have their epigenomes profiled.
Furthermore, saliva (and other bodily fluids) can present challenges with cell isolation as a source material for blood cells in respect to downstream experimentation for reasons such as:                1. Blood is a transporter fluid while saliva is a digestive fluid that can be rich in proteases, enzymes and secreted substances and urine is a excretory fluid consisting of unwanted waste products.        2. Some fluids can have a wide pH range and some of the pH values reported, such as for saliva, would result in death if blood reached that pH (saliva is 6.2-7.4; urine is 4.5-8; blood is 7.35-7.45).        3. Some fluids contain more bacteria than blood.        4. Some fluids contain non-cellular material that varies between individuals and interferes with cell isolation.        5. Some fluids include blood cells, such as T-cells, which can be abundant in blood, but may be rare in other naturally expressed bodily fluids, such as saliva or urine, and are vastly outnumbered by other cell types, such as epithelial cells, unlike in blood.        6. The subset of lymphocyte cells in some bodily fluids, such as saliva, greatly differs from the population of those cell types in blood. For example, only CD4+CD8− T-cells are reported to be found in saliva.        7. Some fluids are produced each day, such as saliva at about a rate of 0.5-1.5 liters per day per person.        
Therefore, there is a need for new methods for isolating rare cells (i.e., T-cells) from saliva and other naturally expressed bodily fluids.
For collecting saliva samples from a large population of people (example: functional genomic studies) who are widely geographically dispersed, several requirements may need to be met for an optimal sample collection device. For example, it may be beneficial to have the sample collection device securely house a toxic preservative solution in a closed chamber. Additionally, the sample collection device may be able to be sent to a donor with the toxic solution safely enclosed. The sample collection device may also allow easy and safe collection of a donor specimen, such as human saliva or urine, with no risk of exposure of the donor to the toxic solution. Furthermore, the sample collection device may allow the donor to safely mix the toxic solution and the specimen (for preservation of the specimen) with no risk of exposure of the donor to neither the toxic solution nor any other hazard. The sample collection device may also allow the donor to send the sample collection device to a laboratory for processing generally “as-is” after securely closing the sample collection device. Finally, the sample collection device may further allow a laboratory technician to receive the sample collection device and safely open it for processing with generally no risk of exposure to any hazards.
Some currently available sample collection devices include, for example, U.S. Pat. No. 7,482,116 which describes a device that utilizes disassociating a barrier to allow fluid communication between a cavity holding the donor sample and a solution, however, embodiments included in the patent are limited to the use of sharp extruding objects and thin pierceable membranes. The thin pierceable membranes can represent a safety hazard to the sample donor as any wrong manipulation (such as with a finger nail) can lead to piercing of the membrane and release of the solution. US patent publication no. 2009/0216213 A1 claims a device that utilizes a pierceable membrane to establish fluid communication between a cavity containing a solution and the donor sample. This can represent a safety hazard to the sample donor as any wrong manipulation can lead to piercing the membrane and exposing the solution. The device also requires exchange of the cap prior to sending the sample to the end user. This can represent a safety hazard as it may expose the sample donor to the potentially toxic solution. Therefore, there is a need for safer and easier to use sample collection devices.
Additionally, the purification process requires cells to maintain their antigen profiles and the epigenomic profiling requires that their epigenome be maintained. To this end, it is necessary to treat the cells in such a way that they are able to generally maintain these features. Currently available treatments generally do not meet this need. For example, U.S. Pat. Nos. 7,267,980 and 7,749,757 disclose solutions containing lysine, glycine and formaldehyde for stabilizing cells from blood. However, those solutions will not protect cells from proteases found in some bodily fluids, such as saliva. Therefore, there is a need for new solutions and methods that will preserve the antigenicity and epigenome of cells in other bodily fluids, such as saliva.